Existing chemical mechanical polishing (CMP) material removal methods use mechanical down force to generate friction between a substrate and a polishing pad. Material removal is conventionally performed at a rate on the order of 1500 nm per minute down to 400 nm per minute. However, reducing the material removal rate below 20 nm per minute is beyond the capability of existing CMP tools primarily due to the minimum down force required to be applied to the substrate to effect any material removal. Improved device formation technologies that allow creation of ever smaller devices would benefit from the enhanced control that lower removal rates would allow but are not possible with existing CMP tools. Thus, what is needed are methods and apparatus for chemical polishing that do not rely on mechanical down force.